/Engine/Source/Runtime/Projects/Public/Interfaces/IPluginManager.h
Stores the specified path, utilizing it in future search passes when searching for available plugins. Optionally refreshes the manager after the new path has been added.
Whether the plugin search path was modified
bool AddPluginSearchPath ( const [FString](API\Runtime\Core\Containers\FString) & ExtraDiscoveryPath, bool bRefresh )